Two New Diterpenoids Formed by Transannular Diels–Alder Cycloaddition from the Soft Coral <i>Sarcophyton tortuosum</i>, and Their Antibacterial and PPAR-β Agonist Activities
Two new cembrane-derived tricyclic diterpenes belonging to the sarcophytin family, namely 4<i>a</i>-hydroxy-chatancin (<b>1</b>) and sarcotoroid (<b>2</b>), together with two known related ones (<b>3</b> and <b>4</b>), were isolated from th...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2024-12-01
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| Series: | Marine Drugs |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1660-3397/22/12/553 |
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| Summary: | Two new cembrane-derived tricyclic diterpenes belonging to the sarcophytin family, namely 4<i>a</i>-hydroxy-chatancin (<b>1</b>) and sarcotoroid (<b>2</b>), together with two known related ones (<b>3</b> and <b>4</b>), were isolated from the soft coral <i>Sarcophyton tortuosum</i> collected off Ximao Island in the South China Sea. The structures of the new compounds were elucidated by extensive spectroscopic analysis, a quantum mechanical nuclear magnetic resonance (QM-NMR) method, a time-dependent density functional theory electronic circular dichroism (TDDFT-ECD) calculation, X-ray diffraction analysis, and comparison with the reported data in the literature. A plausible biosynthetic pathway of compounds <b>1</b>–<b>4</b> was proposed, involving undergoing a transannular Diels–Alder cycloaddition. In the bioassay, the new compound <b>1</b> displayed significant inhibitory activities against the fish pathogens <i>Streptococcus parauberis</i> KSP28, oxytetracycline-resistant <i>Streptococcus parauberis</i> SPOF3K, and <i>Photobacterium damselae</i> FP2244, with MIC values of 9.1, 9.1, and 18.2 μg/mL, respectively. Furthermore, by conducting a luciferase reporter assay on rat liver Ac2F cells, compounds <b>1</b>, <b>3</b>, and <b>4</b> were evaluated for peroxisome proliferator-activated receptor (PPAR) transcriptional activity, and compound <b>3</b> showed selective PPAR-β agonist activity at a concentration of 10 μΜ. |
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| ISSN: | 1660-3397 |